Is the universe built like the internet?

Kate Taylor, 20th November 2012

The universe may be structured a lot like the human brain and even the internet, and similar laws may govern its growth.

Some universal laws appear to be in action, although their nature and origin is hard to pin down.

"By no means do we claim that the universe is a global brain or a computer," says Dmitri Krioukov, of the University of California's Cooperative Association for Internet Data Analysis (CAIDA).

"But the discovered equivalence between the growth of the universe and complex networks strongly suggests that unexpectedly similar laws govern the dynamics of these very different complex systems."

Complex supercomputer simulations of the universe show that the causal network representing the large-scale structure of space and time in our accelerating universe is a graph that's remarkably similar to many complex networks such as the internet, social or even biological networks, he says.

"These findings have key implications for both network science and cosmology," says Krioukov. "We discovered that the large-scale growth dynamics of complex networks and causal networks are asymptotically (at large times) the same, explaining the structural similarity between these networks."

Of course the network representing the structure of the universe is astronomically huge - in fact it can be infinite. But even if it's finite, researchers' best guess is that it is no smaller than 10250 atoms.

Yet the researchers say they have now proved mathematically that the universe's properties don't depend on the network size when it comes to a certain range of parameters, such as curvature and age.

"The most frequent question that people may ask is whether the discovered asymptotic equivalence between complex networks and the universe could be a coincidence," says Krioukov.

"Of course it could be, but the probability of such a coincidence is extremely low. Coincidences in physics are extremely rare, and almost never happen. There is always an explanation, which may be not immediately obvious."